JP5310342B2 - Robot wrist device - Google Patents

Description

  The present invention relates to a wrist device for a robot, and more particularly to a wrist device for a robot that prevents an abnormal increase in internal pressure of a casing of a reduction gear.

  A wrist device for a robot is configured by rotatably attaching a wrist rotating portion having a rotatable end effector mounting member to a distal end portion of an arm. The wrist rotation unit is provided with a speed reduction device that reduces the rotation of the motor and transmits it to the end effector mounting member. The inside of the casing of the speed reduction device is a sealed space. An appropriate amount of lubricant (such as grease) is contained for lubrication.

Although not directly related to the present invention, in Patent Document 1, in order to prevent intrusion of water or the like into the sealed space of the wrist rotating unit, the wrist to which the wrist rotating unit is attached has a sealed structure, and the wrist is sealed. The space and the inside of the arm communicate with each other through a narrow air flow path so that air having a pressure higher than the pressure of the outside air is supplied to the inside of the arm. According to this, since the sealed space of the wrist part is maintained at a pressure higher than the pressure of the outside air, water or the like can be prevented from entering the sealed space of the wrist part from the seal portion, and the inside of the arm and the narrow air can be prevented. Since the sealed space of the wrist connected by the flow path is maintained at the same or slightly lower pressure as the inner space of the arm, it is possible to prevent the lubricant in the sealed space of the wrist from being pushed out into the arm. Is done.
JP 7-75992 A

In Patent Document 1, a motor for driving an end effector mounting member is provided in an arm, and a motor provided in the arm and a speed reducer provided in a wrist rotating unit are connected by a belt transmission mechanism. ing.
If the drive motor for the end effector mounting member is provided not on the arm but on the wrist rotating portion, the rotation transmission configuration is simplified. However, if a motor is arranged on the wrist rotating part, the air temperature in the sealed space of the casing of the speed reducer increases due to the heat generated by the motor, the air pressure in the casing increases due to the temperature rise, and the service life of the sealing member exceeds For example, if it overlaps with an unfavorable condition that exceeds the assumed use condition, the lubricant in the sealed space may leak out from the seal part.

  In the configuration disclosed in Patent Document 1, the pressure in the sealed space of a speed reducer (a speed reducer that decelerates the rotation of the motor and transmits it to the end effector mounting member) provided inside the tip of the wrist rotating portion In addition to this, when the pressure rises due to the air being warmed by the heat of the motor, the lubricant in the sealed space of the speed reducer causes the output shaft of the speed reduction mechanism to move outside. There is a risk of leakage from the sealing portion of the through hole for leading out. In particular, in a small robot, considering that the objects handled by the end effector vary widely and may handle food, the rotation is slowed down by the end effector mounting member provided at the tip of the wrist rotating part. It is the most important issue to prevent the leakage of lubricant from the speed reducer to be transmitted.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a reduction gear that is provided at a tip portion of a wrist rotation portion and transmits rotation to an end effector mounting member. It is an object of the present invention to provide a wrist device for a robot that can prevent a lubricant from leaking outside.

  The first reduction device for the end effector mounting member and the second reduction device for the wrist rotation unit are provided on the two surfaces of the housing of the wrist rotation unit, which are different from each other by 90 degrees, and the end effector mounting member is provided with the first deceleration. A motor that is driven via the device is provided in the housing of the wrist rotating unit, and the first sealed space in the first casing of the first reduction device and the second casing of the second reduction device in the housing of the wrist rotating unit. Since the communication path communicating with the second sealed space is formed, when the pressure in the first sealed space increases, the air in the first sealed space flows to the second sealed space through the communication path, and the first sealed space Abnormal pressure rise in the space is prevented. Further, two valve bodies that open and close by its own weight are rotatably provided at the opening to the first sealed space of the communication path, and the position of the opening to the second sealed space of the communication path is set to a position that satisfies a predetermined condition. Since it set, it can prevent as much as possible that the lubricant in the 1st sealed space and the 2nd sealed space flows into the other party's sealed space through a communicating path. For this reason, the air in the first sealed space can be released to the second sealed space to prevent an abnormal pressure increase in the first sealed space, and at the same time, the lubricant is either one of the first sealed space and the second sealed space. It is possible to obtain an excellent effect of preventing the remaining space from being biased and preventing the remaining space from becoming insufficient of the lubricant, thereby preventing seizure of the first reduction gear and the second reduction gear.

  In the second aspect, the two valve bodies are formed in a shape in which at least the edges on the sides adjacent to each other gradually approach the center line of the valve body in the direction orthogonal to the rotation center from the rotation center side toward the tip. Therefore, it can be prevented that the two valve bodies interfere with each other and cannot be closed.

Sectional drawing of the principal part which shows the 1st Embodiment of this invention Schematic front view showing the relationship between the twist rotation angle of the wrist rotation part and the opening and closing of the valve body The perspective view of the valve body attached near the opening to the 1st sealed space of a communicating path Enlarged perspective view of the valve body shown as a single unit The perspective view which shows the arrangement form of a pipe FIG. 2 is a schematic vertical side view showing the relationship between both sealed spaces and communication paths at each twist rotation angle in FIG. 2. FIG. 6A is a schematic vertical side view showing the relationship between the both sealed spaces and the communication path in a state where the wrist rotating portion is rotated upward at the twist rotation angle of FIG. FIG. 7 is a view corresponding to FIG. 7 in a state where the wrist rotating portion is rotated downward at the twist rotation angle of FIG. FIG. 7 is a view corresponding to FIG. 7 in a state in which the wrist rotating portion is rotated downward at the twist rotation angle of FIG. FIG. 2 equivalent view showing the second embodiment of the present invention FIG. 2 equivalent view showing the third embodiment of the present invention FIG. 2 equivalent view showing a fourth embodiment of the present invention FIG. 2 equivalent view showing a fifth embodiment of the present invention

A first embodiment of the present invention will be described below with reference to FIGS. FIG. 1 shows a distal end portion of a robot body formed by sequentially connecting a plurality of arms so that the arm 1 can be rotated in sequence. In FIG. 1, the arm 1 is front, rear, left, right, in cooperation with other arms (not shown). It can be moved in all directions up and down, and can be twisted and rotated.
The frame 2 that is the main body of the arm 1 is of a plurality of divided types, and a wrist rotating portion 3 is supported on the inside of the tip of the frame 2 so as to be rotatable about the axis W. The flange 4 is supported so as to be rotatable about the rotation center axis F. The flange 4 is an end effector mounting member to which an end effector such as a hand is attached.

  The support structure and rotational drive configuration of the wrist rotating part 3 and the flange 4 will be described. First, the wrist rotating part 3 is mainly composed of a housing 5 having a hollow inside, and the flange 4 is provided in the hollow inside of the housing 5. A motor 6 for rotationally driving the motor is disposed. The rotation center axis W of the wrist rotation unit 3 and the rotation center axis F of the flange 4 are orthogonal to each other, and two surfaces of the housing 5 that are different from each other by 90 degrees, that is, the tip surface 5a orthogonal to the rotation center axis F, and the rotation center A first speed reduction device 7 located on the rotation center axis F of the flange 4 on the side surface 5b orthogonal to the axis W, and a second speed reduction device located away from the rotation center axis F of the flange 4 in the radial direction of the flange 4 8 are arranged. Here, the fact that the first reduction gear 7 is positioned on the rotation center axis F of the flange 4 does not necessarily mean that it is concentric with the rotation center axis F of the flange 4, but is positioned between the flange 4 and the motor 6. It means that.

  The first speed reduction device 7 and the second speed reduction device 8 are configured by housing (built in) the first speed reduction mechanism 11 and the second speed reduction mechanism 12 in the first casing 9 and the second casing 10. The device 8 is configured to be larger than the first reduction gear 7. The first speed reduction mechanism 11 and the second speed reduction mechanism 12 are both constituted by a wave gear speed reduction device, and have an elliptical first rigid cam 13 and second rigid cam 14 as an input portion, and a flexible first wave bearing 15. And second wave bearing 16, flexible cylindrical first flexible external gear 17 and second flexible external gear 18, first rigid internal gear 19 and second rigid internal gear 20 have.

  The first casing 9 of the first reduction gear device 7 is configured by connecting a first rigid internal gear 19 and two casing elements 21 and 22 in three stages and connecting them with bolts (connecting means) 23. The two casing elements 21 and 22 have a cylindrical shape, and the flange 4 is rotatably fitted and supported via a cross roller bearing 24 inside thereof. The flange 4 and the casing element 21 are sealed with an oil seal (seal member) 25.

  The first rigid internal gear 19 has a substantially cylindrical shape, and an annular mounting portion 19a coupled to the two casing elements 21 and 22 is formed on the outer peripheral portion on one end side. The first rigid internal gear 19 has a circular opening in which an internal gear portion 19b is formed on the inner peripheral surface. Therefore, the first casing 9 is configured such that one end surface is opened at the circular opening of the internal gear portion 19 b of the first rigid internal gear 19 and the other end surface is closed by the flange 4. An O-ring groove 26 is formed on the cylindrical outer peripheral surface of the internal gear portion 19 b of the first rigid internal gear 19, and an O-ring (seal member) 27 is fitted in the O-ring groove 26.

  With respect to the first casing 9, a cylindrical casing receiver (fitting portion) 28 is integrally formed on the front end surface 5 a of the housing 5 of the wrist rotating portion 3. The first casing 9 is disposed on the front end surface 5 a of the housing 5 so that the first rigid internal gear 19 is fitted inside the casing receiver 28, and is attached to the casing receiver 28 by bolts (coupling means) 29. It is fixed. In this fixed state, the first casing 9 and the casing receiver 28 are sealed by the O-ring 27 attached to the first rigid internal gear 19.

  The rotating shaft 30 of the motor 6 provided in the housing 5 of the wrist rotating unit 3 protrudes from the front end surface 5 a of the housing 5 into the first casing 9. In the present embodiment, the center axis of the rotating shaft 30 coincides with the center axis F of the flange 4. The rotary shaft 30 and the front end surface 5 a of the housing 5 are sealed by an oil seal (seal member) 31 attached to the front end surface 5 a of the housing 5. A space between the coupling surfaces of the two casing elements 21 and 22 and the first rigid internal gear 19 is sealed with a sealant (not shown) applied to the coupling surfaces. Therefore, the internal space of the first casing 9 is sealed to form a first sealed space 32.

  In the first speed reduction mechanism 11 housed in the first sealed space 32, the first rigid cam 13 is fitted to the rotating shaft 30 of the motor 6 and fixed by a screw 33. The flexible inner ring 15 a of the first wave bearing 15 is fitted to the first wave bearing 15. On the other hand, the first flexible external gear 17 is fixed to the flange 4 by the bolt 34 in a state where the external gear portion 17 a is positioned inside the internal gear portion 19 b of the first rigid internal gear 19. . When the first casing 9 is fitted to the casing receiver 28, the external gear portion 17 a of the first flexible external gear 17 is fitted to the flexible outer ring 15 b of the first wave bearing 15. The external gear portion 17a bends into an elliptical shape, so that the external teeth mesh with the internal teeth of the internal gear portion 19b of the first rigid internal gear 19 at two locations.

  In the first speed reduction mechanism 11, when the rotary shaft 30 rotates, as is well known, the rotation is caused by meshing between the external teeth of the first flexible external gear 17 and the internal teeth of the first rigid internal gear 19. It is decelerated and transmitted to the flange 4, and the flange 4 rotates. For lubrication of the first speed reduction mechanism 11, an appropriate amount of lubricating oil (lubricant) is stored in the first casing 9, that is, in the first sealed space 32.

  The second casing 10 of the second reduction gear 8 includes an inner casing 38 formed by connecting an annular auxiliary inner casing element 36 to a substantially circular dish-shaped inner casing element 35 by a bolt (coupling means) 37, and an outer casing 38. An outer casing 41 is formed by coupling the second rigid internal gear 20 to the casing element 39 with a bolt (coupling means) 40, and the outer casing 41 rotates outside the inner casing 38 via a cross roller bearing 42. The mating support is possible.

  In the second casing 10, the inner casing element 35 and the outer casing element 39 are sealed with an oil seal (seal member) 43. In addition, O-ring grooves 44 and 45 are formed on the joint surface of the outer casing element 39 with the second rigid internal gear 20 and the joint surface of the second rigid internal gear 20 with the side surface 5b of the housing 5, respectively. The outer casing element 39 and the second rigid internal gear 20 are sealed by an O-ring (seal member) 46 fitted in one O-ring groove 44.

  A short cylindrical casing receiver (fitting portion) 47 for positioning the second casing 10 is integrally formed on the side surface 5 b of the housing 5 of the wrist rotating portion 3. Further, a shaft portion 48 is integrally provided on the side surface 5 b of the housing 5 so as to be located in the center with the casing receiver 47. In the present embodiment, the central axis of the shaft portion 48 coincides with the rotational center axis W of the wrist rotating portion 3. An input shaft 49 as an input portion of the second reduction mechanism 12 is supported on the shaft portion 48 via a ball bearing 50 so as to be rotatable.

  The second casing 10 is disposed on the side surface 5 b of the housing 5 so that the outer casing element 39 and the second rigid internal gear 20 are fitted in the casing receiver 47, and is fixed to the housing 5 by bolts 51. A space between the side surface 5 b of the housing 5 and the second rigid internal gear 20 is sealed by an O-ring 52 fitted in an O-ring groove 45 of the second rigid internal gear 20.

  In a state where the second casing 10 is fixed to the housing 5, the tip end portion of the input shaft 49 protrudes outward from the inner casing element 35. The input shaft 49 and the inner casing element 35 are sealed with an oil seal (seal member) 53. Further, a lid body 54 having a bearing case portion 54 a is fixed to the inner casing element 35 with a screw 55. A screw hole (through hole) 56 into which the screw 55 is screwed is formed so as to penetrate the inner casing element 35, and the inside of the second casing 10 is open to the outside. When the screw 55 is screwed into the screw hole 56, the screw hole 56 is sealed with the screw 55.

  By sealing the screw hole 56 with the screw 55 and sealing each part with the oil seals 43 and 53 and the O-rings 46 and 52, the internal space of the second casing 10 becomes a sealed second sealed space 57. It is preferable to apply a sealing agent to the screw 55.

  A ball bearing 58 is mounted on the bearing case portion 54 a of the lid 54, and the upper end portion of the input shaft 49 is rotatably supported by the ball bearing 58. A pulley 59 is rotatably supported on the ball bearing 58, and the pulley 59 is connected to the input shaft 49 by a bolt 60.

  The inner casing element 35 of the second casing 10 is fixed to the frame 2 of the arm 1 by bolts 61. As a result, the wrist rotating unit 3 is cantilevered and supported by the inner casing 38 via the ball bearing 58, the input shaft 49, and the ball bearing 50 so as to be rotatable about the rotation center axis W.

  Although not shown, a motor for driving the wrist rotating unit 3 is disposed in the arm 1, and this motor is connected by a pulley 59 and a belt 62. Therefore, when the driving motor of the wrist rotating unit 3 is activated, the rotation is transmitted to the pulley 59 by the belt 62, and the pulley 59 and the input shaft 49 rotate integrally.

  In the second casing 10, the second rigid cam 14 of the second reduction mechanism 8 is fixed to the input shaft 49 by a bolt 63, and the flexible inner ring 16 a of the second wave bearing 16 is attached to the second rigid cam 14. It is mated. On the other hand, the second flexible external gear 18 is fixed to the inner casing element 35 by the bolt 64 in a state where the external gear portion 18a is positioned inside the internal gear portion 20a of the second rigid internal gear 20. ing. When the second casing 10 is fitted to the casing receiver 47, the external gear portion 18a of the second flexible external gear 18 is fitted to the flexible outer ring 16b of the second wave bearing 16. The external gear portion 18a bends into an elliptical shape, whereby the external teeth mesh with the internal teeth of the internal gear portion 20a of the second rigid internal gear 20 at two locations.

  In the second reduction mechanism 12, when a motor (not shown) in the arm 1 is activated, the rotation is transmitted to the input shaft 49 via the belt 62, and the rotation of the input shaft 49 is second flexible as is well known. The second rigid internal gear 20 rotates by being decelerated by the meshing of the external teeth of the external external gear 18 and the internal teeth of the second rigid internal gear 20. Since the second rigid internal gear 20 is fixed to the housing 5, the wrist rotating unit 3 rotates about the rotation center axis W when the second rigid internal gear 20 rotates. In order to lubricate the second speed reduction mechanism 12, a predetermined amount of lubricating oil (lubricant) is stored in the second casing 10, that is, in the second sealed space 57.

  A communication path 65 for communicating the first sealed space 32 and the second sealed space 57 is provided. The communication path 65 includes a first path 66 formed in the housing 5, a second path 67 formed in the second rigid internal gear 20, and a pipe 68 disposed in the second sealed space 57. It is configured. One end of the first passage 66 opens at the front end surface 5 a of the housing 5, and the other end opens at the side surface 5 b of the housing 5. The second passage 67 passes through the second rigid internal gear 20, and one end communicates with the other end opening of the first passage 66. One end of the pipe 68 is connected to the other end opening of the second passage 67, and the tip (the other end) is opened in the second sealed space 57. In addition, it is preferable to make the inner diameter of the communication path 65 small so that the air passes but the lubricating oil does not easily pass.

  Here, the formation position of the one end opening 65a (one end opening of the first passage 66) in the front end surface 5a of the housing 5 of the communication passage 65 will be described. First, in FIGS. 2A to 2D, the rotation center axis F of the wrist flange 4 is horizontal, and the wrist rotation unit 3 is rotated 90 degrees around the rotation center axis F by twisting the arm 1. 2 is a view of the casing receiver 28 on the front end surface 5a of the housing 5 as viewed from the front direction (the direction of arrow J in FIG. 1) along the rotation center axis F of the flange 4. FIG. Among these, FIG. 2A shows a state in which the rotation center axis W of the wrist rotation unit 3 is horizontal and the second reduction gear 8 is positioned directly beside the housing 5. The arm 1 has a state in which the second speed reduction device 8 is located directly to the left of the housing 5 as a reference position, and can make one rotation clockwise from the reference position and one rotation counterclockwise.

  In FIG. 2A, arbitrary two straight lines L1 and L2 which are orthogonal to each other through the figure center O of the casing receiver 28 are drawn. For simplification of explanation, it is assumed that one of the straight lines L1 coincides with the rotation center axis W of the wrist rotating unit 3. The two straight lines L1 and L2 divide the inner side of the casing receiver 28 (the front end surface 5a of the housing 5) into four regions R1 to R4, but the one end opening 65a of the communication path 65 is divided into the four regions R1. Are formed at a desired position in one desired region, for example, the region R1.

  When the communication path 65 is in a state where the first sealed space 32 and the second sealed space 57 are always in communication, the lubricating oil in the first sealed space 32 passes through the communication path 65 depending on the posture of the wrist rotating unit 3. The case where it flows out to the 2nd sealed space 57 arises. In order to prevent the lubricant from flowing out from the first sealed space 32 to the second sealed space 57, a valve device 69 is provided as shown in FIG.

  3 and 4, the valve device 69 is rotatably supported by the first support base 70 and the second support base 71 by the first support shaft 72 and the second support shaft 73. It consists of two first valve bodies 74 and second valve bodies 75. The first valve body 74 and the second valve body 75 are centered on rotation center axes C1 and C2 on one end side (the axes of the first support shaft 72 and the second support shaft 73 that support the one end side). Thus, it can be rotated in an angle range of 90 degrees, and the rotation is naturally performed by its own weight. In addition, since the 1st valve body 74 and the 2nd valve body 75 are the same support structures, in FIG. 4, only the 1st valve body 74 is illustrated and about the 2nd valve body 75 side, it is the same part. Only the code is described in.

  The first support base 70 and the second support base 71 are located between one end opening 65a of the communication path 65 and two regions R2 and R4 adjacent to the region R1 where the one end opening 65a is located. It is fixed to the front end surface 5a of the housing 5 in a state. As a result, the first valve body 74 and the second valve body 75 rotate in the closing direction by the dead weight of the one end opening 65a of the communication path 65 from the regions R2 and R4 adjacent to the region R1, respectively. Again, for the sake of simplicity, the rotation center axes C1 and C2 of the first valve body 74 and the second valve body 75 are orthogonal to each other and parallel to the two straight lines L2 and L1, respectively. It shall be.

  The first valve body 74 and the second valve body 75 are a first valve in which the shape of the outer edge of the front portion is perpendicular to the rotation center axes C1 and C2 from the rotation center axes C1 and C2 toward the tip. The body 74 and the second valve body 75 are formed in a shape that gradually approaches the center lines T1 and T2, for example, a semicircular arc shape. Thereby, when the 1st valve body 74 and the 2nd valve body 75 rotate in the direction which closes the one end opening 65a of the communicating path 65 with both dead weights, in the case of a rectangular shape, one becomes a support of an other party. However, if it is a semicircular arc, one valve body slides on the outer edge of the other valve body and securely rotates to the position where one end opening 65a is closed. To be able to move.

  Here, the opening / closing operation | movement of the 1st valve body 74 and the 2nd valve body 75 is demonstrated. 2A to 2D show a state in which the rotation center axis F of the flange 4 is horizontal as described above. Of these, FIG. 2 (a) shows both the first valve element 74 and the second valve element 75 with one end opening 65a open (the wrist rotating part 3 rotates clockwise). When the state shown in FIG. 2A is reached, the first valve element 74 closes the one end opening 65a.) When the wrist rotating portion 3 rotates, for example, in the counterclockwise direction from the state of FIG. 2A, the rotation center axis C1 of the first valve body 74 is gradually inclined above the one end opening 65a. Therefore, the first valve body 74 rotates downward about the rotation center axis C1 by its own weight acting on the center of gravity located at a position away from the rotation center axis C1, and closes the one end opening 65a. The second valve body 75 continues to maintain the open state because the rotation center axis C2 continues to be positioned below the one end opening 65a and its own weight continues to act as a moment in the opening direction. The closed state of the first valve body 74 and the opened state of the second valve body 75 are maintained until the state shown in FIG.

  When the wrist rotating unit 3 rotates counterclockwise from the state of FIG. 2B, the rotation center axis C2 of the second valve body 75 is gradually inclined above the one end opening 65a. The second valve body 75 is rotated downward about the rotation center axis C2 by its own weight acting on the center of gravity located away from the rotation center axis C2, and the one end opening 65a is already closed. It overlaps on the valve body 74 of one. Since the 1st valve body 74 is located above the one end opening 65a, it maintains a closed state with the dead weight which acts on the gravity center in the position away from the rotation center axis C2. The closed state of the first valve body 74 and the second valve body 75 is maintained until the state shown in FIG.

  When the wrist rotating unit 3 rotates counterclockwise from FIG. 2C, the rotation center axis C1 of the first valve body 74 is gradually inclined below the one end opening 65a. The first valve body 74 tries to open the one end opening 65a by rotating downward about the rotation center axis C2 by its own weight acting on the center of gravity located at a position away from the rotation center axis C1. Since the weight of the second valve body 75 that is overlaid is acting, the second valve body 75 stops at the position where it is closed, or gradually rotates downward while pushing the second valve body 75 open. When it is rotated counterclockwise by 45 degrees or more from the state shown in FIG. 2C, the first valve body 74 pushes the second valve body 75 and completely rotates downward to open the one end opening 65a. . The second valve body 75 pushed away by the downward rotation of the first valve body 74 is immediately rotated downward by its own weight and again closes the one end opening 65a. This state is maintained until the state shown in FIG.

  When the wrist rotating unit 3 rotates counterclockwise from the state of FIG. 2D, the rotation center axis C2 of the second valve body 75 is gradually inclined to be positioned below the one end opening 65a. The second valve body 75 is rotated downward by its own weight acting on the center of gravity located away from the rotation center axis C2, and opens the one end opening 65a. The rotation center axis C1 of the first valve body 74 is located on the lower side of the one-end opening 65a and gradually goes upright from the inclined state, but until the state shown in FIG. Is kept open.

  The above is the opening / closing operation of the first valve body 74 and the second valve body 75 when the wrist rotating unit 3 rotates counterclockwise, but the wrist rotating unit 3 may also rotate clockwise. It can be inferred from the above explanation.

  The other end opening 65 b (the tip of the pipe 68) in the second sealed space 57 of the communication path 65 with respect to the one end opening 65 a of the communication path 65 opened and closed by the first valve body 74 and the second valve body 75. The position of the (opening) is determined as follows. That is, the other end of the first passage 66 is a position opposite to the flange 4 across the rotation center axis W of the wrist rotating portion 3 as shown in FIG. It is opened at a position outside of 18. The second passage 67 communicating with the other end opening of the first passage 66 is formed in parallel with the rotation center axis W of the wrist rotating portion 3. As shown in FIG. 5, the pipe 68 connected to the second passage 67 is bent at a right angle near the connection end to the second passage 67 and rotates along the inner peripheral surface of the inner casing element 35. It extends until it is below a plane including the center axis W and the rotation center axis F, and is bent at a right angle therefrom and positioned near the inner surface 35 a of the inner casing element 35. Note that FIG. 5 shows the state where the second reduction gear 8 is located directly to the left of the rotation center axis F of the flange 4 (FIG. 2A).

  In order to more accurately describe the position of the tip opening of the pipe 68, that is, the other end opening 65b of the communication path 65, the rotation center axis W of the wrist rotating portion 3, the rotation center axis F of the flange 4, and both rotation center axes A description will be given using three-dimensional coordinates having an axis J orthogonal to both F and W as coordinate axes. First, with respect to the position in the axis J direction, the communication path of the rotation center axis F of the flange 4 is leveled and the second reduction gear 8 is positioned directly to the left and right of the rotation center axis F of the flange 4. When the one end opening 65a of 65 is located on the lower side, in the case of the present embodiment, when it is positioned directly to the right (FIG. 2 (c)), the other end opening 65b is from the lowermost part of the second sealed space 57. Is also determined to be a position that is the same or a certain height or higher than the oil level G of the lubricating oil in the second sealed space 57 in the present embodiment. (See FIG. 6 (c)).

  As for the position of the flange 4 in the direction of the rotation center axis F, the other end opening 65b is on the opposite side of the flange 4 with respect to the rotation center axis W of the wrist rotation unit 3, and the second flexible external gear 18 Between the outer periphery and the inner periphery of the inner casing element 35. With respect to the position of the wrist rotation unit 3 in the direction of the rotation center axis W, the other end opening 65b is close to the inner surface of the inner casing element 35 and is a predetermined distance away from the side surface 5b of the housing 5, specifically, the flange 4 2 (d), the second reduction gear 8 is positioned directly above the rotation center axis F of the flange 4, and the rotation center axis W of the wrist rotation unit 3 is set to be vertical. When the state is set, the predetermined height (first predetermined height) or more than the lowermost part of the second sealed space 57 is constant from the oil level G of the lubricating oil in the second sealed space 57 in the present embodiment. It is determined to be a position protruding beyond the height (see FIG. 6D). Here, the lubricating oil stored in the first sealed space 32 and the second sealed space 57 is a predetermined amount appropriate for the first speed reducing mechanism 11 and the second speed reducing mechanism 12, for example, the first sealed space 32 and the second sealed space, respectively. Assume that an amount corresponding to 60% of the internal volume of the sealed space 57 is stored.

  Next, in the above configuration, the operation of the communication path 65 will be described together with the procedure for assembling the first reduction gear 7 and the second reduction gear 8 to the housing 5 of the wrist rotating unit 3. The first reduction gear 7 is assembled to the housing 5, and then the second reduction gear 8 is assembled. That is, while the flange 4 is rotatably supported inside the two casing elements 21 and 22 via the cross roller bearing 24, the casing elements 21 and 22 and the first rigid internal gear 19 are connected by the bolts 23. Fix and assemble the first casing 9. At this time, a sealing agent is applied to the coupling surface between the casing elements 21 and 22 and the first rigid internal gear 19 to seal the space between the coupling surfaces. Then, an oil seal 25 is inserted between the flange 4 and the casing element 21. Further, the first flexible external gear 17 is fixed to the flange 4 with bolts 34. Then, an O-ring 27 is fitted into the O-ring groove 26 of the first rigid internal gear 19. Further, the first casing 9 faces upward (the first rigid internal gear 19 side is upward), and a predetermined amount of lubricating oil in the first casing 9, in this embodiment, 60% of the internal volume of the first sealed space 32 is provided. Inject.

  On the other hand, the first wave bearing 15 is fitted on the outer periphery of the first rigid cam 13, and then the first rigid cam 13 is fixed to the rotary shaft 30 with a screw 33. Thereafter, the housing 5 is turned downward (the rotary shaft 30 protrudes downward), and the external gear portion 17a of the first flexible external gear 17 of the first casing 9 in the upward state is moved to the first wave bearing. The first rigid internal gear 19 is inserted into the casing receiver 28 while being fitted to the 15 flexible outer rings 15b.

  At this time, when the O-ring 27 is inserted into the casing receiver 28, the inside of the first casing 9 (first sealed space 32) is sealed, and the subsequent insertion of the first rigid internal gear 19 into the casing receiver 28. Accordingly, the internal volume of the first sealed space 32 is reduced. However, since the first valve bodies 74 and 75 are in the open state, the air in the first sealed space 32 passes through the first passage 66 of the communication passage 65 as the internal volume of the first sealed space 32 decreases. Thus, the first passage 66 exits from the other end opening. Thus, the attachment of the first reduction gear 11 to the housing 5 is completed.

  Next, the outer casing element 39 is rotatably supported by the cross roller bearing 42 while assembling the inner casing 38 by connecting the inner casing element 35 and the auxiliary inner casing element 36 of the second casing 10 with the bolts 37. Subsequently, the O-ring 46 is fitted into the O-ring groove 44 of the outer casing element 39, and then the second rigid internal gear 20 is fixed to the outer casing element 39 with the bolts 40 to assemble the outer casing 41.

  Thus, the second casing 10 in which the outer casing 41 is rotatably disposed on the inner casing 38 is assembled. An oil seal 43 is inserted between the inner casing element 35 and the outer casing element 39 of the second casing 10. Further, the second flexible external gear 18 is fixed to the inner casing element 35 of the second casing 10 with a bolt 64.

  On the other hand, the second rigid cam 14 fitted with the second wave bearing 16 is fixed to the input shaft 49 by the bolt 63, and the input shaft 49 can be rotated to the shaft portion 48 of the housing 5 via the ball bearing 50. Attach to. Then, after the O-ring 52 is fitted in the O-ring groove 45 of the second rigid internal gear 20, the second flexible external gear 18 is fitted to the outer periphery of the second wave bearing 16. The second casing 10 is fitted into the casing receiver 47 and fixed to the housing 5 with bolts 61. Thereby, the outer casing 41 of the second casing 10 is fixed to the housing 5.

  Next, for example, a predetermined amount, for example, 60% of the inner volume of the second sealed space 57 is injected into the second casing 10 from the gap between the inner casing element 35 and the input shaft 49, and then An oil seal 53 is fitted between the inner casing element 35 and the input shaft 49. At this time, when the internal volume of the second casing 10 is reduced by the insertion of the oil seal 53, the air in the second casing 10 escapes from the screw hole 56 to the outside along with the reduction.

  Subsequently, the lid 54 to which the ball bearing 58 is mounted is disposed on the inner casing element 35 so that the ball bearing 58 is fitted to the input shaft 49. Next, the screw 55 coated with a sealant is screwed into the screw hole 56 to fix the lid 54 to the inner casing element 35. Thereby, the 2nd casing 10 (2nd sealed space 57) is made into a sealed state. Thereafter, the pulley 59 is fixed to the input shaft 49 with the bolt 60.

  As described above, the first reduction gear device 11 and the second reduction gear device 12 are attached to the distal end surface 5a and the side surface 5b of the wrist rotating unit 3, respectively. The wrist rotating unit 3 is arranged inside the frame 2 of the arm 1, and the outer casing 41 of the second casing 10 is fixed to the frame 2 with bolts 61. Accordingly, the wrist rotating unit 3 is supported in the frame 2 so as to be rotatable about the rotation center axis W. Thereafter, the belt 62 is stretched between the pulley 59 and a pulley of a motor (not shown). The frame 2 is divided into a plurality of parts so that the wrist rotating part 3 can be disposed in the frame 2.

  During the operation of the robot, the arm 1 is moved in all directions, up, down, front, back, left, and right, the wrist rotating unit 3 is rotated around the rotation center axis W by a motor (not shown) in the arm 1, and the flange 4 is in the housing 5. The arm 6 is rotated around the rotation center axis F by the rotation shaft 30 of the motor 6, and the arm 1 is twisted to twist the wrist rotation unit 3.

  During the robot operation, when the motor 6 is energized to rotate the flange 4, the motor 6 generates heat with the energization. The first casing 9 and the second casing 10 are heated by the heat generated by the motor 6, the air temperature in the first sealed space 32 and the second sealed space 57 rises, and the first sealed space 32 and the second sealed space 57. The air pressure inside rises. Since the second sealed space 57 is sealed by screwing the screw 55 into the screw hole 56 in a state where it is in communication with the atmosphere, the motor is initially at atmospheric pressure and has a larger internal volume than the first sealed space 32. The temperature rise due to the heat of 6 is small and therefore the pressure rise is small. On the other hand, the first sealed space 32 is initially at atmospheric pressure like the second sealed space 57, but has a smaller internal volume than the second sealed space 57, and further from the rotary shaft 30 to the first rigid cam 13. Since there is also direct heat conduction to the air, the increase in air temperature due to the heat generated by the motor 6, and thus the increase in pressure is relatively large.

  For this reason, when the air in the first sealed space 32 is warmed by the heat generated by the motor 6 during the robot operation and the pressure rises, the air in the first sealed space 32 passes through the communication path 65 to the second sealed space 57. Flowing. The flow of air from the first sealed space 32 to the second sealed space 57 prevents the pressure in the first sealed space 32 from rising abnormally, and the oil seal 25 or O that seals the first sealed space 32 is used. Even when the ring 27 has exceeded the service life, it is possible to prevent the occurrence of a problem such as the lubricating oil leaking out from the sealed portion of the first sealed space 32 by the oil seal 25 or the O-ring 27 as much as possible. .

  On the other hand, the air pressure in the second sealed space 57 rises due to the inflow of air from the first sealed space 32, but the first sealed air due to the relatively large internal volume (volume of the air portion) of the second sealed space 57. Since the pressure when the inflow of air from the space 32 to the second sealed space 57 stops (when the air pressure in the first sealed space 32 and the second sealed space 57 becomes equal) is not so high, the second sealed Even when the oil seals 43 and 53 and the O-rings 46 and 52 for sealing the space 57 have exceeded the service life, the second sealed space 57 is sealed by the oil seals 43 and 53 and the O-rings 46 and 52. It is possible to prevent the occurrence of problems such as leakage of lubricating oil from the portion as much as possible.

By the way, in order for air to flow from the first sealed space 32 to the second sealed space 57, the one end opening 65a and the other end opening 65b of the communication passage 65 are formed in the first sealed space 32 and the second sealed space 57. It is necessary to be in an air layer above the oil level G and to have both the first valve body 74 and the second valve body 75 open.
In this regard, the robot grips and transports a workpiece with a hand provided on the flange 4 and performs a task of assembling the gripped workpiece on another workpiece, which is usually performed by the wrist rotating unit 3. 6 is performed in a state where the flange 4 is turned downward by rotating it counterclockwise in FIG. 6 around the rotation center axis W. In this state, for example, as shown in FIG. 9, the first valve body 74 and the second valve body 75 open by their own weight, and the one end opening 65a and the other end opening 65b of the communication passage 65 are in the air layer. The air in the first sealed space 32 flows to the second sealed space 57 through the communication path 65.

  Of course, the end effector provided on the flange 4 is not limited to the hand. However, even when an end effector other than the hand is provided, most of the normal robot work is performed with the flange 4 obliquely downward or vertically downward, and the robot work is performed with the flange 4 facing downward. Even if it is not performed, there is always an opportunity to take a posture in which the flange 4 faces downward during one cycle of operation of the robot.

  As described above, when the integral opening 65a of the communication passage 65 is opened, the air in the first sealed space 32 flows out into the second sealed space 57, so that an abnormal pressure increase in the first sealed space 32 occurs. Is prevented.

  On the other hand, the functions of the first valve body 74 and the second valve body 75 are to prevent the lubricating oil in the first sealed space 32 from flowing into the second sealed space 57 by closing the one end opening 65a of the communication passage 65. There is a place to do. When the rotation center axis F of the flange 4 is in a horizontal state, the wrist rotating unit 3 is between the state of FIG. 2A and the state of FIG. 2B, the state of FIG. 6 (b), (c), and (d) when rotating 90 degrees between the state of c) and between the state of FIG. 2 (c) and the state of FIG. 2 (d), respectively. ), One of the first valve body 74 and the second valve body 75 closes the one end opening 65a of the communication passage 65. At this time, the lubricating oil does not flow from the first sealed space 32 to the second sealed space 57 through the communication path 65. Of course, even if the flange 4 is in an upward posture, the first valve body 74 or the second valve body 75 prevents the lubricating oil from flowing out from the first sealed space 32 to the second sealed space 57.

  However, for example, even when the one-end opening 65a is closed as in FIG. 2B, the first sealing is performed as in FIG. 6B showing the state corresponding to FIG. 2B. The lubricating oil level G in the space 32 is higher than the lubricating oil level G in the second sealed space 57. For this reason, when the wrist rotating unit 3 rotates with the flange 4 facing downward, the first valve body 74 and the second valve body 75 are in a state of slightly opening the one end opening 65a. As shown in (a), when the entire communication path 65 is below the lubricating oil level G in the first sealed space 32, the lubricating oil in the first sealed space 32 passes through the communication path 65 to the second sealed space 57. There is a risk of flowing in.

  However, as shown in FIG. 8B, when a part of the communication path 65 rotates to an angle that exceeds the lubricating oil level G in the first sealed space 32, the first sealed space 32 to the second sealed space 57. Lubricant flow to the stops. Then, as shown in FIG. 8A, the state in which the communication path 65 is below the lubricating oil level G in the first sealed space 32 is only a moment in the fast movement of the robot. Oil hardly flows from the first sealed space 32 to the second sealed space 57.

  Between the state of FIG. 2 (a) and the state of FIG. 2 (d) (equivalent between FIG. 6 (a) and FIG. 6 (d)), the 1st valve body 74 and the 2nd valve body Both 75 open one end opening 65a. However, in this case, since the second sealed space 57 is directly beside the first sealed space 32 or above the first sealed space 32, the lubricating oil in the first sealed space 32 passes through the communication path 65 to the first. 2 There is no flow into the sealed space 57. However, in this case, if the state in which the flange 4 faces upward as shown in FIG. 7 continues for a long time, the lubricating oil in the first sealed space 32 flows to the second sealed space 57 through the communication path 65. It is possible. However, the fact that the flange 4 is more upward than the state shown in FIG. 7 is rare in the robot operation, and even if it is only a moment in the movement of the robot, the lubrication in the first sealed space 32 is performed. Oil hardly flows through the communication path 65 to the second sealed space 57.

  Since the first valve body 74 and the second valve body 75 are a kind of check valve, it is impossible to prevent the lubricating oil from flowing out from the second sealed space 57 to the first sealed space 32. However, the outflow of the lubricating oil from the second sealed space 57 to the first sealed space 32 is prevented by setting the position of the other end opening 65b of the communication path 65 at the predetermined position as described above. . That is, when the lubricating oil flows out from the second sealed space 57 to the first sealed space 32, the lubricating oil surface G in the second sealed space 57 is positioned above the lubricating oil surface G in the first sealed space 32. There are times when it may occur. This corresponds between the state of FIG. 2A and the state of FIG. 2D, and between the state of FIG. 2C and the state of FIG. 2D.

  However, in the state of FIG. 2D, the second end opening 65b of the communication path 65 is above the lubricating oil surface G in the second sealed space 57 as shown in FIG. The lubricating oil is prevented from flowing out from the sealed space 57 to the first sealed space 32. In the state of FIG. 2 (d), even if the wrist rotating unit 3 rotates so that the flange 4 faces downward, the other end opening 65 b is opposite to the flange 4 with respect to the rotation center axis W of the wrist rotating unit 3. Therefore, as shown in FIG. 9, the other end opening 65b separates upward from the lubricating oil surface G and is not immersed in the lubricating oil. Accordingly, the outflow of the lubricating oil from the second sealed space 57 to the first sealed space 32 is prevented.

  Further, in the states of FIGS. 2A and 2C, the amount of lubricating oil in the first sealed space 32 and the second sealed space 57 is 60% of the internal volume. 6 (a) and FIG. 6 (c), the first sealed space 32 and the second sealed space 57 are located above the line that bisects the top and bottom (in this case, the horizontal rotation center axis F). Thus, the oil level G in the second sealed space 57 is slightly higher than the oil level G in the first sealed space 32. However, in the state of FIG. 2A, as shown in FIG. 6A, the one end opening 65a is located above the oil level G of the second sealed space 57, and in the state of FIG. As shown in FIG. 6B, since the other end opening 65b is located above the oil level G of the second sealed space 57, the lubricating oil from the second sealed space 57 to the first sealed space 32 is obtained. Will not flow.

  Further, when the wrist rotating unit 3 is torsionally rotated between the state of FIG. 2A and the state of FIG. 2D, or between the state of FIG. 2C and the state of FIG. Also in the case of twisting and rotation, the lubricating oil in the second sealed space 57 is prevented from flowing out to the first sealed space 32 in the same manner as described above.

  Between the state of FIG. 2 (a) and the state of FIG. 2 (d), and between the state of FIG. 2 (c) and the state of FIG. When the flange 4 rotates in the downward direction at the center, the other end opening 65 b is located on the opposite side of the flange 4 from the rotation center axis W of the wrist rotating portion 3. A part of the other end opening 65 b side or the other end opening 65 b is separated from the lubricating oil surface G in the second sealed space 57 and never falls below the lubricating oil surface G. Accordingly, the outflow of the lubricating oil from the second sealed space 57 to the first sealed space 32 is prevented.

  As described above, according to the present embodiment, the second sealed space 57 is of course prevented while preventing the lubricating oil from flowing in and out through the communication path 65 between the first sealed space 32 and the second sealed space 57. That is, it is possible to prevent an abnormal increase in air pressure in the first sealed space 32 and to prevent the lubricating oil from leaking out of the first reduction gear 7.

  Further, since the lubricating oil is prevented from flowing in and out through the communication path 65 between the first sealed space 32 and the second sealed space 57, the lubricating oil is prevented from flowing into the first sealed space 32 or the second sealed space 57. Is not ubiquitous. Accordingly, the amount of lubricating oil in each of the first sealed space 32 and the second sealed space 57 can be maintained at an appropriate amount, and seizure of the first speed reduction mechanism 11 and the second speed reduction mechanism 12 can be effectively prevented.

  Of course, depending on the posture of the wrist rotating unit 3, the lubricating oil may flow out through the communication path 65 between the first sealed space 32 and the second sealed space 57. However, since the posture in which the lubricating oil flows in and out between the first sealed space 32 and the second sealed space 57 is known, it is possible to take such a posture when creating the robot operation program. By avoiding this, it is possible to more reliably prevent the lubricating oil from flowing in and out between the first sealed space 32 and the second sealed space 57.

The present invention is not limited to the first embodiment described above and shown in the drawings, but can be expanded or changed as follows.
The position where the one end opening 65a of the communication path 65 is provided may be provided in the region R2 as in the second embodiment of the present invention shown in FIG. 10, or the third embodiment of the present invention shown in FIG. It may be provided in the region R3 as in the embodiment, or may be provided in the region R4 as in the fourth embodiment of the present invention shown in FIG. Furthermore, as in the fourth embodiment of the present invention shown in FIG. 13, L1 does not necessarily have to coincide with the rotation center axis W of the wrist rotation unit 3 when the casing receiver 28 is viewed from the direction of the arrow J. Further, the rotation center axes C1 and C2 of the first valve body 74 and the second valve body 75 need not be parallel to L1 and L2.

The O-ring 27 that seals between the first casing 9 and the casing receiver 28 may be mounted on the casing receiver 28 side.
If the O-ring is provided between the outer casing element 39 and the casing receiver 47 in the second casing 10, the two O-rings 46 and 51 of the second rigid internal gear 20 become unnecessary.
The through hole of the second casing 10 is not limited to the screw hole 56.
The first speed reduction mechanism 11 and the second speed reduction mechanism 12 may be composed of a normal gear train.
The components of the first casing 9 and the second casing 10 are not limited to those of the embodiment.
The valve bodies 74 and 75 may be trapezoidal.

  In the drawings, 1 is an arm, 2 is a frame, 3 is a wrist rotating part, 4 is a flange (end effector mounting member), 5 is a housing, 6 is a motor, 7 is a first reduction device, 8 is a second reduction device, 9 Is a first casing, 10 is a second casing, 11 is a first speed reduction mechanism, 12 is a second speed reduction mechanism, 25 is an oil seal (seal member), 27 is an O-ring (seal member), and 28 is a casing receiver (fitting) Part), 32 is a first sealed space, 43 is an oil seal (seal member), 46 is an O-ring (seal member), 47 is a casing receiver, 49 is an input shaft, 52 and 53 are O-rings (seal members), 54 Is a lid, 55 is a screw, 56 is a screw (through hole), 57 is a second sealed space, 65 is a communication path, 65a and 65b are one end opening and the other end opening of the communication path, 68 is a pipe, 69 is a valve device 74 is the first valve body, and 75 is the second valve body. It is.

Claims (2)

A wrist of a robot having a rotatable end effector mounting member and rotatably mounting a wrist rotating unit including a motor for driving the end effector mounting member on a distal end portion of an arm including a motor for driving the wrist rotating unit In the device
From the first reduction gear for the end effector mounting member and the rotation center axis of the end effector mounting member, which are located on the rotation center axis of the end effector mounting member, on two surfaces different from each other by 90 degrees of the housing of the wrist rotation unit Providing a second speed reducer for the wrist rotating part located away in the radial direction;
The first speed reducer and the second speed reducer decelerate the rotation of the motor built in the wrist rotating part and transmit it to the end effector mounting member in the first casing and the second casing, respectively. Comprising a first reduction mechanism and a second reduction mechanism that reduces the rotation of the motor built in the arm and transmits it to the wrist rotation part;
The first casing has one end surface on the housing side open, and a fitting portion provided on one outer surface of the different outer surfaces of the housing has at least one of the fitting portion and the first casing. The inside is a first sealed space by being fitted with a seal member that seals between the two on one side,
The second casing has a through-hole that communicates the inside with the outside, and is attached to the other outer surface of the different outer surfaces of the housing, and the through-hole is closed after being attached to the housing. The inside is a second sealed space,
Providing a communication path that communicates between the first sealed space in the first casing and the second sealed space in the second casing, and opening the communication path to the first sealed space; When the fitting portion is divided into four regions by any two straight lines orthogonal to each other through the center of the figure when viewed from the rotation center axis direction of the end effector mounting member, the four regions At least two valve bodies that are provided so as to be located in one of the areas and that open and close the opening into the first sealed space and rotate in the closing direction and the opening direction by their own weight; Provided to rotate in the closing direction from the two regions adjacent to the one region provided with the opening,
The opening of the communication path into the second sealed space is opposite to the end effector mounting member across the rotation center axis of the wrist rotation unit, and the rotation center axis of the end effector mounting member is horizontal. In this state, when the second speed reducer is positioned directly above the rotation center axis of the end effector mounting member, the second reduction device is at least a first predetermined height above the lowermost part of the second sealed space. A robot, wherein the speed reducer is provided at a position that is at least a second predetermined height higher than a lowermost portion of the second sealed space when the speed reducer is positioned directly beside the rotation center axis of the end effector mounting member. Wrist device.   The two valve bodies are formed such that at least the edges on the sides adjacent to each other gradually approach the center line of the valve body in the direction perpendicular to the rotation center from the rotation center side toward the tip. The wrist device for a robot according to claim 1, wherein the wrist device is a robot.

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